Diaz is a Spanish surname meaning Son of Jacob.
- Persons
- Diaz (rapper), a Norwegian rapper of Spanish descent
- Alyssa Diaz (1987–), American actress
- Aarón Díaz (1982–), Mexican actor
- Adolfo Camilo Díaz (1963–), Asturian language writer
- Armando Diaz (1861–1928), Italian World War I commander
- Bartholomew Diaz or Bartolomeu Dias (c.1450-1500), Portuguese explorer
- Bernal Díaz del Castillo (c.1492-1581), Spanish conquistador
- Cameron Diaz (1972–), American actress
- Edgardo Díaz (1960–), Panamanian-Puerto Rican creator of the band Menudo
- Franklin Chang-Diaz (1950–), Costa Rican-American physicist and astronaut
- Gloria Diaz (1950- ), Miss Universe 1969
- Guillermo Diaz (contemporary), American actor
- Joe Diaz (1938–), Mexican-American boxing trainer
- José E. Díaz, Paraguayan general
- Justino Díaz (1940–), Puerto Rican opera singer
- Manny Diaz, (contemporary), American politician, mayor of Miami, Florida
- Matt Diaz (1978–), American Major League Baseball player of the Atlanta Braves
- Matthew Diaz (c. 1965–), United States Naval officer and lawyer
- Nate Diaz, MMA Fighter
- Nick Diaz, MMA Fighter
- Narcisse Virgilio Diaz (1808–1876), Spanish-French artist
- Osvaldo Diaz (1981–), Paraguayan football player and Olympic contestant
- Porfirio Díaz (1830–1915), Mexican dictator, President of Mexico 1876–1911
- Rodrigo Díaz de Vivar (c.1044–1099), known as "El Cid Campeador", a Castilian nobleman, then military and political leader who conquered and governed the city of Valencia
- Ron Diaz (contemporary), American radio talk show host
- Ricardo Diaz, a fictional drug lord that appears in the games Grand Theft Auto: Vice City and Grand Theft Auto: Vice City Stories
- Sharmilla Diaz, singer from Mumbai, India
- Stella Diaz (1984–), Sports Illustrated Swimsuit Model Search finalist, Puerto Rican beauty and fashion model
- Sully Diaz (contemporary), Puerto Rican model and actress
- Susy Diaz (1965–), Peruvian vedette
- Tommy Diaz (1977–), musician, performer of "The Carnival," President/CEO of Confidential Recordz
- Victor Diaz, Dominican Baseball player
- Yamila Diaz (1976–), Argentinian professional model
- Yanelis Yuliet Labrada Diaz, (1981–), Cuban martial arts medalist at the 2004 Olympics
- Yanqui Diaz (1976–), Cuban boxer
- Place names
- Diaz, Arkansas, USA
- Other
- Jaime Diaz Producciones, Argentinian animation studio
